This proposal is submitted in response to the PA # 99-134 "Exploratory and Development Grants for Mental Health Intervention Research (R21)." AIDS-related deaths have declined due to improved treatments, but new HIV infections continue to occur at a stable rate. Although new infections must involve already infected persons, few prevention programs are available for persons living with HIV. Particularly conspicuous by their absence are interventions for men who have sex with men (MSM), a subgroup that includes more than 50% of HIV+ persons in the U.S. The central goal of the proposed research is to develop and provide an initial evaluation of an intensive risk reduction intervention that reflects the unique prevention needs of HIV+ MSM. Three research phases are proposed, consistent with the R21 mechanism. First, during a formative research phase, 50 HIV+ MSM will participate in focus groups (n = 30) and key informant interviews (n = 20), and will complete quantitative surveys (n = 50) in order to (a) tailor intervention content, (b) assess barriers to participation, and (c) pilot our evaluation instruments. Second, during the intervention development phase, an intensive, group-based risk-reduction intervention for HIV+ MSM will be developed and manualized. Intervention design will be guided by the empirical literature, our formative research, and the Information-Motivation-Behavioral Skills (IMB) model. During this phase, the intervention will be piloted with a small group of MSM, and revised based on this pilot experience. Third, during an evaluation phase, 80 HIV+ MSM will be randomized to either: (a) HIV risk reduction intervention, or (b) a standard care control condition. Assessments of sexual risk behavior and hypothesized risk antecedents will be obtained at baseline, post-intervention, and a 3 month follow-up. The feasibility and acceptability of the intervention will be evaluated with qualitative and quantitative data, including intervention attendance, patient satisfaction ratings, and exit interviews. Preliminary evidence of intervention effectiveness will be obtained through effect-size estimates and a comparison of the treated and control group on sexual risk behavior and theoretical antecedents of risky sex. If effective, the proposed intervention promises to have a significant public health impact by averting new HIV infections and improving health outcomes among HIV+ MSM.